1. Field of the Invention
The invention relates to a backlight module, and more particularly to a backlight module having a reflective shell and a bezel that is tightly combined with the reflective shell.
2. Description of the Related Art
Liquid crystal displays (LCDs) are widely applied in various electrical products such as personal digital assistants (PDAs), notebook computers, digital cameras, digital camcorders, mobile telephones, computer monitors, liquid crystal televisions, and the like because the technology for manufacturing the LCDs are rapidly developed and the LCDs have the advantages of light weight, thin thickness, and power-saving and radiation-free properties. The application field of the LCDs is rapidly expanded because the manufacturers have constructively paid attention to research and development, and adopted large-scale production apparatuses to constantly enhance the quality of the LCDs and reduce the price of the LCDs. However, because the LCD panel of the liquid crystal display is a display panel that cannot emit light rays itself, a backlight module is needed to provide light rays and achieve the display function.
FIG. 1A is a partially exploded view showing a conventional backlight module, and FIG. 1B is a partially enlarged, cross-sectional view showing the backlight module taken along the x-z cross-section of FIG. 1A and viewed from the −y direction. Referring to FIGS. 1A and 1B, the backlight module 10 includes a bezel 11, a light guide plate (LGP) 12, a cold cathode fluorescent lamp (CCFL) 13 and a reflective shell 14. The bezel 11 has a bezel base 11a and several bezel side plates 11b connected to the bezel base 11a. Several protrudent positioning portions 11c are formed on top surfaces of the bezel side plates 11b. The LGP 12 is disposed on the bezel base 11a and has a side surface spaced apart from the bezel side plate 11b by a predetermined distance. The bezel 11 has an inner wall that may be coated with a reflective material, or a reflective plate may further be disposed between the LGP 12 and the bezel base 11a. The CCFL 13 is disposed on the bezel base 11a and is positioned between the bezel side plate 11b and the side surface of the LGP 12. The reflective shell 14 has a reflective shell top plate 14a and a reflective shell side plate 14b connected to the reflective top plate 14a. The reflective shell top plate 14a has several positioning holes 14c corresponding to the protrudent positioning portions 11c, respectively, and each of the positioning holes 14c is close to a connection portion between the reflective shell top plate 14a and the reflective shell side plate 14b. The protrudent positioning portions 11c may be inserted into the positioning holes 14c, respectively, to combine the reflective shell 14 with the bezel 11, as shown in FIG. 1C, wherein the light rays output from the CCFL 13 are reflected by the bezel 11 and the reflective shell 14 , and then incident to the LGP 12 via the side surface of the LGP 12. The LGP 12 guides the light rays to be output from a top surface of the LGP 12 so that the light rays may be directly incident to the LCD panel.
However, it is to be noted that the protrudent positioning portion 11c and the positioning hole 14c are simply engaged with each other without any fastening and fixing design. Thus, the reflective shell 14 tends to be separated from the bezel 11 along the z direction when an external force is applied thereto, as shown in FIG. 1D. In this case, the light rays of the CCFL 13 are output from a gap between the reflective shell top plate 14a and the top surface of the LGP 12, and the light-leakage phenomenon, which greatly influences the brightness quality of the backlight module 10, is caused.